1. Field of the Invention
The present invention relates to a carrying system for carrying a workpiece to a processing zone, and to a processing equipment. More particularly, the present invention relates to a carrying system for carrying a workpiece to be painted between a loading zone and a painting zone.
2. Description of the Related Art
FIG. 12 is a side elevation of a painting equipment 1 in a first example of the related art and FIG. 13 is a schematic plan view of the painting equipment 1 in the first example of the related art. The painting equipment 1 includes a painting machine 3 and a carrying machine 4. The carrying machine 4 carries a workpiece 2 along a circular route 9 between a loading zone 7 where the workpiece 2 is loaded on and unloaded from the carrying machine 4 and a painting zone 6 where the workpiece 2 is painted. The painting equipment 1 paints the workpiece 2 by spraying paint on the workpiece 2 placed in the painting zone 6 by the painting machine 3. In the painting equipment 1 in the first example of the related art, the painting machine 3 is disposed at the center of the circular route 9. The carrying machine 4 has holding units 5a and 5b disposed on the diametrically opposite sides, respectively, of the painting machine 3. The holding unit 5b is in the loading zone 7 when the holding unit 5a is placed in the painting zone 6. A workpiece 2 held by the holding unit 5a placed in the painting zone 6 is painted. A workpiece 2 held by the holding unit 5b placed in the loading zone 7 is changed for another one by an operator. The carrying machine 4 can carry workpieces 2 held by the holding units 5a and 5b between the painting zone 6 and the loading zone 7 by turning the holding unit 5a and 5b along the circular route 9.
FIG. 14 is a plan view of a painting equipment 11 in a second example of the related art. The painting equipment 11 in the second example of the related art includes a painting machine 12 and a carrying system. The carrying system has two carrying machines 13a and 13b. The carrying machines 13a and 13b have tables 5a and 5b, respectively. The tables 5a and 5b support workpieces, respectively. The tables 5a and 5b are moved along straight routes, respectively, between a painting zone 6 where a workpiece is painted and a loading zone 7 where a workpiece is loaded and unloaded. The two carrying machines 13a and 13b are disposed on the opposite sides, respectively, with respect to the painting machine 12. The carrying machines 13a and 13b include straight carrying rails, respectively.
The painting equipment 11 in the second example of the related art, as compared with the painting equipment 1 in the first example of the related art, facilitates the optional distance layout between the painting zone and the loading zone 7 and can carry a large workpiece. The carrying machines 13a and 13b can be individually operated. Therefore, a workpiece supported by the carrying machine 13b can be carried while the workpiece supported by the carrying machine 13a is being painted or being replaced with another workpiece and hence loss time is short. The painting equipment 11 in the second example of the related art is disclosed in JP-A 2000-168950.
The painting equipment 11 in the second example of the related art has the straight rails for carrying workpieces. Therefore, the distance between each loading position for the carrying machines 13a and 13b increases inevitably if the distance between each painting position for the carrying machines 13a and 13b is shortened. Consequently, space needed for installing the painting equipment 11 increases. If the two loading positions are spaced a long distance apart, one operator assigned to work for loading workpieces alternately on the carrying machines 13a and 13b needs to move a long distance for loading workpieces alternately on the carrying machines 13a and 13b and the ease of operation is low.
On the other hand, when the distance between the loading positions for the carrying machines 13a and 13b is shortened, the distance between each painting position for the carrying machines 13a and 13b increases inevitably. Consequently, space necessary for installing the painting equipment 11 increases. If the two painting positions are spaced a long distance apart and the single painting machine 12 is used for alternately painting workpieces disposed at the two painting positions, the painting machine needs to move a long distance for painting workpieces alternately on the carrying machines 13a and 13b, and hence the ease of operation is low. The same problems reside also in carrying systems other than those for painting equipments.